Class 10r sat a test

Class 10R sat a test. The mean mark of the class was 70%. There are 30 students in class 10R, 20 of whom are boys. The mean mark for the boys in the test was 62%.

In this problem, we are given the details of a class (10R) that took a test. The mean mark of the class was 70%, and we are provided with the number of students, as well as the mean mark for the boys. Using these details, we will calculate the mean mark for the girls in the class.

Explanation:
We know the following information:

Total number of students in class 10R: 30
Number of boys in the class: 20
Mean mark of the entire class: 70%
Mean mark of the boys: 62%

To calculate the mean mark of the girls, we can use the following steps:

Calculate the total marks for the class and the boys separately.
Subtract the total marks of the boys from the total marks of the class to get the total marks for the girls.
Divide the total marks of the girls by the number of girls (which is 30 - 20 = 10) to find their mean mark.

Solution:

Total marks for the class = Mean mark of the class × Total number of students = 70% × 30 = 2100%
Total marks for the boys = Mean mark of the boys × Number of boys = 62% × 20 = 1240%
Total marks for the girls = Total marks for the class - Total marks for the boys = 2100% - 1240% = 860%
Number of girls = 30 - 20 = 10
Mean mark for the girls = Total marks for the girls ÷ Number of girls = 860% ÷ 10 = 86%

Answer:
The mean mark for the girls in the class is 86%.